Na-Ion Full Cell: Electrochemical Study Using Prussian Blue Cathode and Tin Sulphide (SnS) Anode with Additive-Free Ether-Based Electrolyte System

Abstract

Nowadays sodium-ion battery technology is becoming more popular among researcher as it has been considered as an alternative to lithium-ion batteries. As an alternative to the state-of-the-art lithium-ion battery technology, sodium-based research needs to come out with an easily adaptable option satisfying adequate energy density which can cover the dearth of the demand for lithium-ion batteries in near future. However, the current sodium technology is still lacking to reach enough energy requirement at the cheaper price point. Recent research trend has arrogated hard carbon anode as conventional graphite is still not an adequate performer for sodium. In addition, NVP has been chosen as one of the best options as cathode due to having higher energy density. Combining NVP and hard carbon, carbonate-based electrolyte with an additive (FEC) is conjunct to build a sodium-ion full cell.1 However, the overall cost of producing this system is still high compared to lithium technology.2 Hence, achieving an adequate energy density at low-cost is an open challenge for the current generation researchers. In this work, we merge two systems: an alloy-based anode and high rate capable cathode in conjunction with an additive-free electrolyte. For the first time, a Na-ion full cell is fabricated combining SnS anode,3 Prussian blue (PB) cathode and NaClO4-TEGDME electrolyte.4 The electrodes were used without any carbonaceous coating. In addition, both the electrode materials were prepared using a rapid bulk synthesis pathway which benefits the time of material preparation, hence can easily be applied in large-scale production. The cathode works nearly 3 V vs. metallic sodium while the anode works mostly below 1.2 V (Fig. 1a). Hence, the overall combination produces an average of 1.8 V full cell (Fig. 1d). Capacity coming from the full cell is nearly 80 mAh g-1 PB (Fig 1c) which corresponds to 135 Wh Kg-1 for the gravimetric energy density. Fig. 1b demonstrates that a single coin cell is capable of powering a LED lamp. Figure 1